Bowel cancer samples that have been stored for up to a century will be analyzed to try to solve the mysterious rise of the disease in young people.
Despite the majority of bowel cancers still being found in older adults, the rise in younger patients has been seen around the world.
This includes in the UK where bowel cancer rates have increased by 75% in the under-24s since the early 1990s - but scientists are unclear why.
The basement at St Mark's The National Bowel Hospital has a unique collection of tens of thousands of archived cancer samples. These are now going through advanced scientific analysis to understand what caused each cancer and what's changed over the decades.
Holly, 27, is one of a growing number of young people getting the disease. Her bloating and weight loss were originally put down to irritable bowel syndrome until she became so ill she ended up in A&E. The young actress was diagnosed with advanced bowel cancer and needed aggressive treatment when she was just 23.
Science doesn't have a clear answer either. Everything from obesity and ultra-processed foods, to antibiotics and the microbiome to air pollution and microplastics have been suggested.
Dr Kevin Monahan, a consultant gastroenterologist at St Mark's hospital, said: We need to develop ways that we can prevent these cancers effectively. In the UK, rates have increased by 51% in those aged 25-49 since the early 1990s although the majority of bowel cancers still occur in older adults.
Prof Trevor Graham, from the Institute of Cancer Research, believes a particular kind of E. coli could be to blame, damaging DNA and leading to cancer. The unique archive of bowel cancer samples offers an unprecedented opportunity to track changes over time and potentially uncover the root causes of this troubling trend.
